3815664 - Error in logs: "Data validation failed. Please check your data in case of error"

When booking Iberia flights, upon selecting 'Book and Continue' on the 'Review and Book' page, an error with "Error Code: ar-40000" gets displayed.

In Service Logs the following error is returned: 

<DescText>Unable to proceed - Failed on provider side</DescText>
<OwnerName>1A</OwnerName>
</Error>
<Error>
<DescText>Data validation failed. Please check your phone data in case of error</DescText>
<OwnerName>IB</OwnerName>

When booking Iberia flights, an error ar-40000 is displayed. In Service Logs the following error is captured: "Data validation failed. Please check your data in case of error". , KBA , CON-SRV-TRV-ADM-LAN , View Airlines , CON-CA , Cross Applications , Problem